Arc welding guns with consumable electrode wire



ARC WELDING GUNS WITH CONSUMABLE ELECTRODE WIRE Filed Nov. 9, 1955 A.BASSOT 2,900,488

2 Sheets-Sheet l 27 6' I l 25 I i Q a Fig.2

INVENTOR ANDRE BASSOT B AM,

ATTORNEYS United States Patent ARC WELDING GUNS WITH CONSUMABLEELECTRODE WIRE Andr Bassot, Boulogne-sur-Seine, France, assignor to LAirLiqui'de, Societe Anonyme pour lEtude et Exploitation des ProcedesGeorges Claude, Paris,

rance Application November 9, 1955, Serial N 0. 545,912

Claims priority, application France November 18, 1954 3 Claims. (Cl.219-130) The present invention concerns arc welding guns with aconsumable wire which may constitute the electrode, which is thenconsumable, or which may be distinct from the electrode which is thennot consumable. The invention particularly relates to guns of thegeneral type in which the gun body supports both a mechanism for movingthe wire and a motor for driving said mechanism.

The latter comprises, generally, two rollers between which the Wire tobe driven passes. The motor is an electric motor the shaft of which canbe coupled with the driving roller of the driving mechanism only bymeans of a costly speed reducer, the weight and bulk of which add tothose, already important of the motor.

A main object of the invention is to obviate these drawbacks. Anotherobject is to arrange the parts of the welding guns of the above generaltype and of the associated equipment with .a view to improve theirconvenience in use. The invention is characterized chiefly in that themotor for driving the mechanism which drives the consumable wire on thegun is a volumetric hydraulic motor supplied with driving fluid from asource outside the gun.

From this principal definition of the invention it may be noted that:

A hydraulic motor may be built entirely of light mate rials (lightalloys and plastics) and consequently does not substantially increasethe weight of the gun;

It may, with a suitable choice of the pressure of the driving fluid,operate at a high torque with a reduced speed of rotation, which makesit possible to omit the speed reducer of the wire driving mechanism;

The adjustment of the speed of the volumetric motor is easily obtainedby an adjustment of the flow rate of the driving fluid, and thiswhatever may be the variations in pressure.

The invention has for further objects to provide an arc welding gun inwhich:

(a) The source of fluid for supplying the hydraulic motor for drivingthe wire is a volumetric pump driven by an electric motor and preferablya capsule type pump, and, for instance, a gear pump.

(b) The hydraulic motor is preferably of the same type as the pump whenthe latter is reversible.

(c) The fluid pumped and forced towards the motor is utilized, at theoutput from the latter, as a cooling medium for the gun, the coolingcircuit for the gun then coinciding, partly at least, with the circuitof the pump and of the hydraulic motor.

(d),The volumetric pump is driven by a constant speedelectric motor, andthe output of the hydraulic motorwhich determines the speed ofdisplacement of the "ice the displacement of this same wire, provided onthe gun.

(g) The motor driving the wire-pulling mechanism ac cording to (f) isthe electric motor controlling the pump which supplies the hydraulicmotor provided on the gun.

(h) The mechanism for pulling the wire, according to (f) is a hydraulicmotor mounted on the delivery side of the pump in series with thehydraulic motor provided on the gun.

Other objects of the invention will be set forth in the followingdescription of various examples of embodiment of this invention,represented in the accompanying diagrammatic drawings wherein:

Figure l is a diagrammatic assembly elevation, with sections of a firstform of embodiment of an arc welding gun, with a consumable electrodeusing a protective gas.

Figures 2, 3, 4 and 5 show the general arrangement of the main elementsof an arc welding station with welding wire, using an improved gunaccording to the invention.

As explained above, the invention consists mainly in driving themechanism for actuating the welding wire which constitutes a consumableelectrode, by a volumetric hydraulic motor mounted on the body of thegun and supplied with a driving fluid under pressure by any suitableoutside source, and preferably by a volumetric pump.

The invention relates particularly to the combination, with the weldinggun, of a volumetric hydraulic motor consisting of a gear pump with areversed circuit for acting as a motor, and supplied with driving liquidby a gear pump driven by an electric motor.

The gun shown in Figure 1 is designed for welding in a protectiveatmosphere, and with cooling by a water circulation. The wire 1, whichconstitutes the consumable electrode, wound otf a remote reel, passesthrough a flexible sheath 2 connected with the gun, and engages guidingelements 3 and 4 arranged on either side of two driving rollers 5 and 6;it comes out of the gun in a contact part 7 connected with the part 4through a conducting tube 8 around which a sleeve 9 is provided for thecirculation of the cooling water. A bathe-sleeve 10 determines thedirection of this circulation, for which the inlet is at 11 and theoutlet at 12 through a duct 13 provided in the handle 14 of the gun andin which a cable 15 is arranged for feeding electric current to thecontact parts 4 and 7. Argon, which constitutes the protective gas forthe welding arc is brought through the output nozzle 16 of the gun,through the duct 17 in the handle and through the annular space 18between the sleeve 9 and the sleeve 19.

According to the invention, the driving roller 5 which, with thepressing roller 6 pulled back by a spring in a known manner, constitutesthe mechanism for the motion of the wire 1 is driven by a volumetrichydraulic motor which, in the example of embodiment considered, is agear motor mounted on the body of the gun. According to one feature ofthe invention, the driving roller 5 is coupled directly with the motor,i.e. without any intermediate speed reducer. To this effect it may bekeyed directly on the outer extension on one of the axles of the pinions20 of the motor 21. Consequently, the arrangement of the motor and wiredriving mechanism on the gun may have a very small bulk and, in anycase, considerably smaller than that of an electric motor of the samepower with its speed reducer. The weight also is substantially less inthe case of the invention, since, in addition to the omitting of thespeed reducer, the hydraulic gear motor or the like does not requireheavy metals like copper but may be made out of light metal alloys andplastic materials of low specific gravity. It is obvious, further, thatthe circuit for the circulation or" the driving fluid for supplying themotor being identical with the gun cooling circuit, the power supply tothe motor is ensured with no weight increase as compared with a watercooled gun, everything else being the same.

The supply pump 22 for the motor is placed, for instance, on the fixedstand which supports the reel 2.3.from which the wire 1 is led to thegun through the flexible sheath 2 (Figures 1 and 2). It is connected, onits suction side, at 24, with a cold water source of a suitable type andits delivery side is connected through any suitable flexible pipe 25with the input 26 to the motor 21 placed on the gun and the output ofwhich 27 is connected to the inside of the sleeve 9 (Figure 1). The pump22 is driven by an electric motor 28 coupled with the pump eitherdirectly or through a suitable reducer.

In the case of the diagram of Figure 2, the Wire 1 is wound off the reel23 by the pull exerted by the rollers and 6 mounted on the gun, butthere may be provided, also, as in the case considered in the diagram ofFigure 5, a pulling mechanism consisting, for instance, of two rollers5a and 6a and placed between the wire reel 23 and the pulling rollers5--6 provided on the gun. These rollers 5a6a are placed, for instance,at the entrance to the flexible sheath 2 connected with the gun at 3a(Figure 1). In this case, the driving roller 5a is conveniently coupledwith the shaft of the pump and the conditions are so determined that thespeed of the linear displacement imparted to the wire 1 be the same atthe outputs of each pair of rollers or that, preferably, the speeds atthe output from the rollers 5a6a be slightly less than that at theoutput from the rollers 56 on the gun. The arrangement of the adjustingmeans for that speed varies according to whether a variable or constantspeed electric motor 28 is used. In the first case it is sufficient toadjust the speed of this electric motor by means of any one of thedevices already used in known arc welding stations.

If a constant speed electric motor is used, the following solutions maybe used:

An adjustable output pump is used;

A constant output pump is used.

In the second case, the liquid fiow rate delivered to the motor isvaried by shunting the latter. It is possible, amongst otherarrangements, to adopt that indicated in the diagram of Figure 3. Inthis arrangement, the hydraulic motor 21 is shunted by a derivation onwhich an automatic element is interposed for controlling the section ofthe passage offered to the liquid. This arrangement is constituted, forinstance, by a differential piston 2929a, one end 29a of which forms avalve movable with respect to a fixed seat 30. For a given pressure inthe conduit 25 the piston is in equilibrium under the thrusts applied oneach one of the two different areas 29 and 29a and by the spring 31. Thereaction of the latter is adjusted by the screw- 32 or other movablestop. This equilibrium position of the piston corresponds to a givenopening of the valve 29a and consequently to a predetermined liquid flowrate through the conduits 25-13 and 333333 and to a given speed of themotor. If the load applied to the latter varies, and if the speed of themotor tends to decrease or to increase in consequence, the pressureinside the conduit 25 rises or drops and the piston 29-29a is moved inthe suitable direction for moving the flap 29a for bringing back thespeed of the motor 21 to the set speed.

In case of an accidental blocking of the wire driving mechanism, and ofa stopping of the motor 21, a delivery valve 34 loaded by an adjustablespring 35 allows the water to pass from the conduit 25 to the conduit 33and to the cooling circuit for the gun.

The diagram of Figure 4 corresponds to that of Figure 3 but whenunwinding rollers such as 5a--6a (Figure 5) are used at the outlet fromthe wire reel 23, these unwinding rollers being no longer driven by thepump 22 as 4 in the case of Figure 5 but by a motor 21a (Figure 4)identical with the motor 21 which drives the rollers 5-6 mounted on thegun. The two motors 21a and 21 are mounted in series in the delivery ofthe same pump 22 driven by the constant speed electric motor 28. Theadjustment of the speed for the two motors simultaneously is effected bymeans of the differential piston 2929a, the operation of which remainsthat described motor mounted on said body and directly coupled with saidmechanism, a volumetric pump remote from the gun body and having itsoutlet connected to the inlet of said hydraulic motor, an electric motorfor driving the pump, and means for supplying said pump with a hydraulicfluid, said hydraulic fluid being used also as a cooling medium for thegun body.

2. In an electric arc welding gun with a consumable electrode wire movedthrough the gun, a gun body provided with means for guiding the wire,with a mechanism for moving the Wire and with means for supplying saidWire with an electric welding current, a hydraulic motor mounted in thebody gun and operatively coupled ith said mechanism, a hydraulic pumpremote from the gun body, the outlet of said pump being connected to theinlet of said hydraulic motor, means for supplying said pump with ahydraulic fluid, a constant speed electric motor for driving thehydraulic pump, and a bypass device adapted to shunt the hydraulic motorand including a valve responsive to the pressure of the fluid forcedinto the hydraulic motor by the pump for keeping constant the speed ofsaid hydraulic motor.

3. In an electric arc-welding gun with a consumable electrode wire movedthrough the gun and fed to the latter by a mechanism driven by avariable speed electric motor, a gun body provided with a means forguiding the wire, with a mechanism for moving the Wire and with meansfor supplying said Wire with an electric Welding current, a hydraulicgear motor mounted on said body and directly coupled with saidmechanism, a volumetric pump remote from the gun body and having itsoutlet connected to the inlet of said hydraulic motor, said pump beingdriven by the electric motor provided for driving the mechanism whichfeeds the electrode wire to the gun body, and means for supplying saidpump with a hydraulic fluid, said hydraulic fluid being also used as acooling medium for the gun body.

References Cited in the file of this patent UNITED STATES PATENTS1,731,502 Paterson Oct. 15, 1929 2,190,927 Kennedy Feb. 20, 19402,278,975 Crawford Apr. 7, 1942 2,391,972 Huiford Jan. 1, 1946 2,423,190Kennedy July 1, 1947 2,490,593 Kay, Dec. 6, 1949 2,526,035 Miller Oct.17, 1950 2,596,708 Moore May 13, 1952 2,606,267 McElrath Aug. 5, 19522,753,688 Bunch July 10, 1956 FOREIGN PATENTS 132,651 Australia June 2,1949

